1. Field of the Invention
This invention relates to a comfort rewind mechanism for a seat belt retractor.
2. Description of the Prior Art
Seat belt retractors of the emergency locking type are designed to permit withdrawal of seat belt webbing against the bias of the rewind spring so that the belt may be buckled about the wearer. Such retractors permit further extension of the belt as well as retraction of the belt as the wearer moves about in his seat and are provided with a locking mechanism which prevents extension of the belt in emergency conditions, such as in the event of a sudden deceleration of the vehicle. The rewind springs of such retractors of necessity exert a substantial rewind force and it has been found that the pressure of the spring bias is uncomfortable to the wearer, especially in the shoulder area.
It has been suggested in several U.S. patents to provide a means of eliminating the tension exerted by the rewind spring. Exemplary of such patents are U.S. Pat. Re. No. 29,095 to Heath and U.S. Pat. No. 3,851,836 to Sprecher, U.S. Pat. No. 3,869,098 to Sprecher and U.S. Pat. No. 4,002,311 to Fisher et al. In each of these patents, means are provided which totally block out the force of the rewind spring after the belt is buckled about the user and then extended further and retracted from the extended position.
The prior comfort designs are of the so-called "tension elimination" design, that is, the rewind spring is blocked out when in use, and while providing improved comfort for the user, can be misused in that an excess amount of belt may remain about the user during operation of the vehicle. Moreover, such designs require a separate releasing mechanism to permit retraction of the seat belt. These mechanisms, such as a mechanical or solenoid door release, add cost and complexity to the comfort mechanism system.
It would be desirable if a comfort mechanism for a seat belt retractor were provided which alleviates the above-mentioned problems. One such device is that disclosed in co-filed application of Joseph Cachia, entitled "Comfort Mechanism for Seat Belt Retractor", Ser. No. 791,618, in which a series of comfort zones are provided by utilizing an additional rewind spring which exerts a lower rewind force when the main spring is blocked out. Such embodiments, however, provide high (and low) comfort zones at various predetermined positions of seat belt extension, and hence, the user must adjust his seating position accordingly if the comfort mechanism feature is desired to be utilized. It would be desirable if there were provided a comfort mechanism of the tension reducing type which was not restricted in use to such predetermined positions of comfort zones and also was self-releasing.